Conventionally, the size of pads (Al electrodes) provided in a semiconductor device has been reduced, along with their interval (pitch) getting narrower. Typically, a passivation film is formed so as to cover pads in a semiconductor device, with an opening part formed on the passivation film to expose a portion of each of the pads.
However, in a semiconductor device wherein a probing test is performed before a bump is formed on a pad, conditions of the probing test (such as accuracy of the probe) depend on the size of an opening part of the passivation film in which the opening part was formed so that the pad is exposed. For example, if the pitch of the pads is reduced to 30 μm or less, the opening part formed on the passivation film is rendered square-shaped with a side length of about 15 μm. In this case, although it is necessary to keep the tip diameter of the probe for use in the probing test always to 10 μm or less, the cost of such a probe is very expensive and unsuitable for mass production.
In addition, the strength of the probe inevitably decreases in order to provide the probe with high pin-counts of about 100 to 1000 pins while maintaining its high-accuracy positioning. This is because of the submicron accuracy required to maintain its high-accuracy positioning (accuracy in three mutually-perpendicular directions).
In the present circumstances as stated above, miniaturization of the pads may make the proving test difficult or increase the cost of the probing test, particularly with a semiconductor device wherein a plurality of pads are aligned in one direction.
Also, in a semiconductor device wherein the probing test is performed after a bump has been formed on the pad, the pitch is limited to about 30 μm to 40 μm, with the side length of the square-shaped pad being limited to about 20 μm to 30 μm in order to perform the probing test. Additionally, with such a semiconductor device, if a defect is found by the test after a bump has been formed, it is difficult to determine whether the defect had existed before the bump was formed, or the defect arose during the formation of the bump.
[Patent Document 1]
Japanese Patent Application Laid-open No. 2003-068736